I. Field of the Invention
The invention relates generally to an energy conserving heat exchange system for use with an apparatus which utilizes heated fluid supplied by a fluid heater supply tank, and more specifically, to such a system which utilizes safety valves to prevent contamination of fresh fluid supply in the event that a rupture occurs in the system.
II. Summary of the Present Invention
A common example of devices which utilize a heated fluid is a dishwasher which utilizes heated water supplied from a water heater tank, The water which is supplied to the dishwasher is used to clean the dishes and collect debris and food particles which are removed from the dishes. When the washing cycle is completed, the water is drained from the dishwasher and it has been a common practice to discharge the water directly into a drain. Such a system is disadvantageous in that the discharge fluid contains a substantial amount of heat energy which is wasted and lost when the fluid is drained from the system. In addition, a substantial amount of energy is expended in heating fresh water which is supplied to the water heating tank so that high temperature water is available for the dish-washer. Thus, it would be advantageous to provide a heat exchanger so that the heat energy contained in the fluid discharged from the dishwasher could be transferred to fresh fluid. Thus, less energy need be expended to heat the fresh water once it enters the water heater tank. In this manner the operating costs of the dishwasher can be substantially reduced.
In addition, it is further advantageous to provide such a heat exchange system in which the contaminated discharge fluid is prevented from coming in contact with the fresh fluid. Although such a separation of fluids is commonly provided in heat exchange systems during normal operation of the system, a rupture in the heat exchanger will permit the two fluids to come in contact with each other and thereby contaminate the fluid throughout the fluid system. Furthermore, a substantial decrease in pressure of the fresh fluid at the input of the system can cause contaminated fluid to flow toward and contaminate the fresh water source. Thus, it would be advantageous to provide a safety mechanism by which contaminated fluid is prevented from flowing into the fluid heater tank or into the fresh fluid supply.